The present invention relates to an electric drive for performing a swiveling or rotary movement with a secondary part and a corresponding primary part. In particular, the present invention relates to a press with such a drive.
In applications using direct drive technology, it is generally necessary for the motor to be matched to a high degree to the installation conditions. This means that a plurality of variant embodiments of one motor type need to be provided by the manufacturer. Furthermore, the technological and technical complexity involved in the manufacture of electric machines increases with the variety of different motor types or physical sizes of a product series of motors.
When using direct drive technology, a plurality of special embodiments of an individual motor are realized for ring-shaped and arc-shaped motor geometries with an axial and radial arrangement by virtue of the fact that the complete motor is modified. This modification ranges from the connection technology to the electromagnetically active parts. Thus, for example, the rotors and stators are manufactured from different lamination cuts for different diameters. This results in expensive technical solutions, extended delivery times and more complicated stockkeeping of spare parts for special motors.
A specific problem associated with drives results for plungers which are required for moving the male die or the female die of a deep-drawing, stamping or other press up and down. Press drives are nowadays generally equipped with hydraulic drives, in particular for high pressing forces. These drives are limited in terms of the regulation possibilities. Progressive technologies in the field of material reshaping or separation require more intervention possibilities on the drive side in the reshaping or cutting process, however, in particular also in order to increase the productivity of the plant. Problems associated with wear and therefore lack of sealtightness in the case of hydraulic drives also increase the maintenance complexity and can damage the environment or require an increased amount of complexity in terms of environment protection. Furthermore, the hydraulic oils used need to be changed after specific use times, which costs resources and money.
In general, it would therefore be desirable to use electric drives for presses since better regulation possibilities exist with such drives. In addition, problems associated with lack of sealtightness would then no longer arise and the maintenance complexity would also be reduced.
Independently of the problem of regulation described above, there is the problem with large electric machines that they generally need to be constructed especially and produced only in small numbers. This results in comparatively high costs related to production numbers, in particular also with regard to the drives used.